Advances in semiconductor processing and logic design have permitted an increase in the amount of logic that may be present on integrated circuit devices. As a result, computer system configurations have evolved from a single or multiple integrated circuits in a system to multiple hardware threads, multiple cores, multiple devices, and/or complete systems on individual integrated circuits. Additionally, as the density of integrated circuits has grown, the power requirements for computing systems (from embedded systems to servers) have also escalated. Furthermore, software inefficiencies, and its requirements of hardware, have also caused an increase in computing device energy consumption. In fact, some studies indicate that computing devices consume a sizeable percentage of the entire electricity supply for a country, such as the United States of America. As a result, there is a vital need for energy efficiency and conservation associated with integrated circuits. These needs will increase as servers, desktop computers, notebooks, Ultrabooks™, tablets, mobile phones, processors, embedded systems, etc. become even more prevalent (from inclusion in the typical computer, automobiles, and televisions to biotechnology).
Power management for an integrated circuit such as a processor is often based on pre-computed values that seek to limit power consumption based on various tradeoffs. To this end, a processor can be configured to operate at various power and performance states. At least some of these performance states may exceed a guaranteed operating frequency and operating voltage for one or more cores when electrical and other constraints are met. Typically a processor includes an electrical design point (EDP) that provides a worst case power/current consumption level that preemptively prevents violation of such constraints. In addition, a processor may be configured with hard limits on a maximum frequency permitted for each number of active cores. Yet performance losses can occur at such levels as cores of a multicore processor routinely enter into and exit from low power states.